Tensioning device for cables



Dec.23, i958 R. c. ROEBLING 2,865,600

E TENSIONING DEVICE FOR CABLES Filed Aug. 5, 1955 INVENTOR @kf/MEM] MEMATTORNEYS United States Patent TENSIONING DEVICE FOR CABLES Robert C.Roebling, Skidaway Island, Ga.

Application August 3, 1955, Serial No. 526,093

4 Claims. (Cl. 254-67) This invention relates to a wire cable terminalfitting for attaching the cable to an object to which tension is to beapplied through the cable.

One of the objects of the invention is to provide a fitting of the typedescribed, in which the adjustment of the cable tension may be madewithout imparting torque to the cable.

Another object of the invention is the provision of an adjustable cabletensioning device, in which the point of attachment of the cable theretois offset with respect to the line of thrust of the tension adjustingmeans, so that the fitting will not twist under the stress incident toadjustment, and therefore, no tool is required to hold the device whilethe tension adjustment is being made.

A more specic object of the invention is to provide a device, asdescribed, fundamentally functioning as a turnbuckle, including a framehaving a longitudinal guideway therein non-round in cross-section, and asleeve reciprocably but non-rotatably guided therein, having an anchorcord fixed thereto and extending from one end of said frame, said sleevehaving a threaded socket which cooperates with an adjusting screwnon-reciprocably mounted in said frame coaxial with said socket andcooperating with said sleeve to adjust the longitudinal position of saidsleeve with respect to said frame, the latter having anchorage means fora cable adjacent its opposite end, external to said guideway and offsetfrom the axis of said adjusting screw.

Still another object of the invention is to provide locking means forsaid screw to prevent its rotaryV and reciprocable movement with respectto said frame.

Other objects of the invention will appear as the following descriptionof a practical embodiment thereof proceeds.

In the drawing which accompanies and forms a part of the followingspecification, and throughout the figures of which the same referencecharacters have been used to designate identical parts:

Figure l is a perspective View of the fitting shown attached to the endof the cable to be tensioned;

Figure 2 is a plan View of the fitting shown in Figure 1; l

Figure 3 is a longitudinal section taken along the line 3-3 of Figure 2;

Figure 4 is a front elevation of the fitting;

Figure 5 is a cross-section taken along the line 5 5 of Figure 3.

Referring now in detail to the disclosure of the several figures, thenumeral 1 represents as a whole the frame of the fitting which is formedwith the longitudinal guideway 2. Said guideway in the illustratedembodiment of the` invention is a channel of` rectangular.cross-section,preferably square, with parallel sides 3' and 4 and an integral bottom5, which is of less length than the sides, so as to provide adjacent oneend an opening 6. In general, it is contemplated that the fitting willbe used with the bottom 5 ofthe Channel uppermost, so that the openofthe sleeve and the inserted screw 25. f e

ing 6 may be regarded as being in the top of the guideway.

The sides 3 and 4 are connected at their ends adjacent the opening 6 bya cross piece 7 formed with a notch 8 converging downward from the top,and communicating with the opening 6. The sides of said notch areconvex, which sides merge into a bottom that is semicylindrical, thecross piece by virtue of the notch constituting a fairleader for thepassage of an anchor cord, as will appear. A pair of spaced wings 9 and10 extend upwardly from the outer face `of the bottom 5 in parallelplanes perpendicular thereto. Said wings are provided near the end ofthe fitting opposite the cross piece 7 with aligned apertures 11 and 12offset an appreciable distance from the guideway 2, in which the pin 13is journaled, bridging the space between said wings, and forming ananchorage for the hook or eye at the end of the cable to be tensioned.In the drawing, the cable is designated at 14, and having the eye 15.

The anchor cord 16 extends from the end of the fitting 1, throughthenotch 8. It is of conveniently short length, and provided at its outerend with a suitable anchor 17, designed to be stationarily held by afixed support. The end of the anchor cord within the fitting 1 issecured to a sleeve 18, which is reciprocable but nonrotatable withinthe guideway 2. The sleeve 18, as shown, is tubular, having a bore 19 atone end which fits the anchor cord, and through which the anchor cord isinserted. The opposite end of the sleeve is counterbored, the inner endof the counterbore forming a conical shoulder 20 adjacent its juncturewith the bore 19. The outer end of the counterbore is threaded, forminga socket 21. The end of the anchor cord is fastened to the cable in someconventional manner, usually by a molten socketing metal. The sleeve maybe of any suitable shape, but is here shown as being cylindrical, withthe exception of a narrow intermediatevzone which is of a shapecomplementary to the cross-sectional shape of the guideway, that is, inthe present instance, square, as indicated at 23, so that it slidablyfits the surrounding structure of the guideway, but prevents anytorsional stress being cornmunicated by the sleeve to the anchor cord.The opening 6 provides access of the sleeve to the guideway from theunder side, the sleeve being presented to the guideway in an inclinedmanner.

The end of the guideway opposite the notch 8 is closed by a transversewall 24 through the perforation of which an adjusting screw 25 isinserted, said screw being freely reciprocable in said aperture. Thescrew has an inner threaded portion 26, an intermediate thrust collar27, and an outer cylindrical portion 23 having a kerf 29 in its outerend. The thrust collar rests against the end wall 24, and the threadedportion 26 interengages with the threaded socket 21, so that the actionof the screw when tightened is to draw the sleeve 18 inwardly of thefitting 1 and thereby shorten the length of the anchor cord extendingfrom the fitting, thus placing tension upon the cable anchored to thepin 13.

In the form of the invention shown, the open vside of the guideway isbridged intermediately by a plate 22, the purpose of which is to reducefriction caused by binding when the screw is hardto turn. Without thisfourth side of the square, the binding forces are unbalanced and canbuild up without limit. The plate 22 is preferably located far enoughfrom the cross piece 7 to allow for the aligning of the sleeve withinthe guideway after it has been inclinedly inserted through the opening6. The plate is also preferably of sufficient lengthf as to underlie theguideway throughout the extent of travel of the square portion 23 of thesleeve. This provides underlying support for the reciprocatorylunitconsisting Y 3 When the --cable 14 -is under tenson, the fitting 1 willposition itself with the anchor cord and the cable 14 in rectilinearalignment, so that the direction of thrust of the adjusting screw willbe offset atan acute angle from the direction ofy the cable. Thisrelationship of parts prevents torque being transmitted to the cablewhen the screw 2S is` tightened, for in order for torque to bedeveloped, the entire guideway would have to rotate about the axis ofthe cable at the point represented by the pin 13, which it obviouslycannot do. Since the imposition of torque in either direction upon thecable either shortens it or lengthens it, a precise tension adjustmentcannot be obtained if such torque is present. The absence of thedevelopmentof torque in the cable incident to the l adjustment of thetension. in the present invention permits a precise adjustment to bemade;

The screw is locked in any position ofadjustment by means of the loopclamp 30, which freely surrounds theI outer cylindrical portion 28 ofthe screw, and having perforated lugs 31 and 32 which rigidly lock theclamp when tightened by means of the screw 33, which passes freelyvthrough the perforation in the lug 31 and threads into the perforationof the lug 32. The plate 10 has a portion 34 extending forwardlytherefrom to a position in which it lies laterally against the lug 31,

and having a perforation 3S registering axially with the perforations inthe lugs 31 and 32, the screw 33 passing through the perforation 3S andfixing the locking clamp against the extended portion 34. Assuming, forexample, that the cable terminal tting of the present invention wereinter-calated in the line of tension of a guy cable supporting a stackwhich might be vaffected by wind pressure, in the absence of the rigidlocking means afforded by the locking clamp 36, if the wind were to blowagainst the stack in such direction as to sway it slightly toward thecable, the thrust collar 27 would obviously move away from the end wall24 a slight distance,

and when the wind pressure became relieved, the stack would sway back tovertical, bringing the thrust collar with heavy impact against the endwall 24. This would put a heavy strain upon both the cable and anchorcord, which is avoided by the locking means for the screw 25, asdisclosed, since with the locking means rigidly clamped about the screwand immovably held by the extended portion of the plate 3l), it would beimpossible for the thrust collar to come out of contact with the wall 24so that the swaying of the stack would be taken up by the progressivestraightening of the cable without any unpactive strain.

While I have in the above description disclosed what l believe to be apractical embodiment of the invention, it will be understood by thoseSkilled in the art that the specific details of construction andarrangement of parts, as shown, are by the way of example and not to beconstrued as limiting the scope of the invention.

What I claim is:

l. Tensioning device for cables comprising a body member provided with atubular guideway therethrough of non-ro-und cross-section having an endwall at one end with a hole therethrough and having a bridge piece atthe other end formed with a divergent sided notch opening laterally withrespect to said guideway, a bifurcated wing extending longitudinallyoutward from the side of said guideway toward which said notch lares, apin supported by said wing bridging the space between the bifurcations,the bridging portion of said pin forming a connecting means for theattachment 4of a cable, an elongated slide nonrotatably reciprocable insaid guideway having a portion thereof of complementary cross-sectionalsize and shape with respect to the crosssection ofsaid guideway, a screwextending freely through thehole in said wall having a shoulder at anintermediate point-,abutting Ysaid Awall,` said screw being threadedlycoupled to `said slide for drawing it toward said connect- ,Y

ing means, one Side Quaid-ninaaggravarsi/seguid end wall, a clamp locksecured to the extending portion of said side and clampably engagingthat part of said screw which extends outwardly beyond said shoulder, aexible member fixed to said slide extending from the end opposite saidscrew and through said notch for anchoring said tension device to anextraneous object, the side of said guideway toward which said notchllares being formed with an opening between said notch and wing forpermitting the insertion of said slide, the opposite side of saidguideway being formed with an opening extending from said bridge piece,of a length at least equal to that of said slide, to make room for themanipulation of said slide in inserting it, and aligning it in saidguideway coaxially with said screw.

2. Tensioning device for cables comprising a body member provided with atubular guideway therethrough of non-round cross-section having an endwall at one end with a hole therethrough and having a bridge piece atthe other end formed with a divergent sided notch opening laterally withrespect to said guideway, a bifur-` cated wing extending longitudinallyoutward from the side of said guideway toward which said notch flares, apin supported by said wing bridging the space between the bifurcations,the bridging portion of said pin forming a connecting means for theattachment of a cable, an elongated slide nonrotatably reciprocable insaid guideway having a portion thereof of complementary crosssectionalsize and shape with respect to the cross-section of said guideway, ascrew extending freely through the holel in said end wall having ashoulder at an intermediate point abutting said wall, said screw beingthreadediy coupled to said slide for drawing it toward said connectingmeans, one side of said wing extending beyond said end wall, a clamplock secured to the extending portion of said wing and clampablyengaging that part of said screw which extends outwardly beyond saidshoulder, and a exible member fixed to said slide extending from the endopposite said screw and through said notch for anchoring said tensiondevice to an extraneous object.

3. Tensioning device for cables adapted to be intercalated betweensections thereof, comprising a body member formed with a guideway ofnon-round crosssection having -an end wall, said body member having awing outside said guideway extending longitudinally thereof and having aportion overhanging said guideway, a slide nonrotatablyv mounted in saidguideway to which one cable section is adapted to be connected, a screwfreely passing through a hole in said end wall having threadedconnection with said slide, said screw having an elongated head abuttingsaid end wall and under- Y lying the overhanging portion of said wing,and means at its outer end for turning it, said wing having a connectionfor the other section of the cable laterally offset from the axis ofsaid screw, and a loop clamp having its bight embracing said elongatedhead, and its limbs positioned adjacent the overhanging portion of saidwing, and a screw passing through registering holes in said wing andlimbs for tightening said clamp and securing it to said wing. i

4. Tensioning device for cables comprising a body member providing atubular guideway therethrough of y polygonal cross-section having an endwall at one end with a hole therethrough, a screw extending freelythrough said hole and an appreciable distance into said guideway,l saidscrew having a shoulder rotatably abutting the exteriorof said bodymember and means by which said screw may be turned, a slide reciprocablewithin saidA guideway of exterior shape and size to fit said guideway`nonrotatably, said screw being threadedly coupled to slide forreciprocating the latter, *an outwardlyextending 5 6 cable sectioncarried by said slide, said body member References Cited in the tile ofthis patent p'rOVd'ed .a Sl-Ot beyond Bald guideway t0 P permitinsertion of said slide with the correlated cable section into saidguideway when assembling, and a bridge 469,889 Spad@ Mar- 1 1892 piecespanning said slot at the end of said body member 5 113311741 Qlllgllaet al June 14 1921 on the side of the axis of said screw opposite saidwing, 2,120,497 Helffl'lch June 14 1938 engaged by said correlated cablesection for diverting 2471642 Nevllle July 11 1941 said correlated cablesection toward coaxial relationship with the cable section anchored tosaid wing when said FOREIGN PATENTS cable sections are mutuallytensioned by said screw. 10 444,207 France Aug. 1, 1912

